Nowadays, the ability of modeling freeform objects is increasingly important and most of the CAD systems lack the geometry modeling techniques that can efficient process models with complex shapes or topologies. Based on this reason, this thesis explores several techniques which can be extensively used in the modeling of complex freeform objects....[ Read more ]

Nowadays, the ability of modeling freeform objects is increasingly important and most of the CAD systems lack the geometry modeling techniques that can efficient process models with complex shapes or topologies. Based on this reason, this thesis explores several techniques which can be extensively used in the modeling of complex freeform objects.

More specifically, a comprehensive discussion is first given about constraint-based and feature-based modeling to set up the framework for modeling free-form objects. A new design automation approach for customized design product, shell mapping, is developed and demonstrated its applications for the apparel industry to eliminate the repetitive effort in designing fashion products to fit different body sizes. Using this approach, the coarse design is first constructed for a reference model. A set of constraint operators are developed to relate the geometric entities of this design to the feature template of the reference model. Next to the constraint coarse design, another layer is applied to perform the "parametric design" for the complicate models. A constraint solving method helps to establish the bijective mapping in the 3D space surrounding the design works. This layer is composed of a set of shells and flexible to customize the shell number and offset. Thus, the shell mapping is an efficient tool to enhance the efficiency in the design of freeform objects. The technique contributes to the design automation of freeform geometry products based on a reference model.

A tool for implanting local details to a freeform model is developed based on the duplicated skin algorithm. A new approach, the duplicate skins algorithm, is introduced to construct compatible meshes for the underlying objects. Devising compatible representations of freeform models is the fundamental of a number of applications, such as the auto-transfer the customized product, n-ary shape morphing, and local geometry feature capture. The algorithm can be applied to a broad range of free-form models. This algorithm complements the earlier algorithm by introducting local features modifications to the coarse design.

Furthermore, a number of detail modeling techniques are also investigated in this thesis. Aside from the local shape editor based on the duplicate skins algorithm, a sketch input based wrinkling tool is described which mimics the typical designer's input for modeling the wrinkle shape of deformable objects in various fabric materials.

Benefiting from the significant features of above tools, the designer is provided with an efficient and intuitive toolbox for the creative design of products with freeform geometry.